Why do Indian ignore sanitation?

last month I had a tour to India,visited some scenic spots such as Puri and Varanasi. What impressed me most was not Indian profound culture，the streets are full of bull sh*it ，stink of it spread everywhere i've been. What's more disgusting,there are many rubbish dumps and corpses of creatures floating on the Ganges River. Isn't there a general awareness that residents should maintain environmental sanitation? I can't understand it